But you can always Sleeve two bits (or more )of string together.
I'd say its like Gunman said,mostly dependent on the individual gun, the sum + fit of the parts that count, which would vary a wee bit with each gun of equal grade from the same maker.
Another answer might be.."Hopefully, mine!"
cheers
franc
I have had a few, & looked at many more Francottes & can't say I remember having seen one with head cracks...